Investigation of the relationship between the burden of raised ICP and the length of stay in a neuro-intensive care unit

Shaw, M., Moss, L. , Hawthorne, C., Kinsella, J. and Piper, I. (2018) Investigation of the relationship between the burden of raised ICP and the length of stay in a neuro-intensive care unit. In: Heldt, T. (ed.) Intracranial Pressure & Neuromonitoring XVI. Series: Acta neurochirurgica supplement (126). Springer, pp. 205-208. ISBN 9783319657974 (doi: 10.1007/978-3-319-65798-1_42)

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Objectives: Raised intracranial pressure (ICP) is well known to be indicative of a poor outcome in traumatic brain injury (TBI). This phenomenon was quantified using a pressure time index (PTI) model of raised ICP burden in a paediatric population. Using the PTI methodology this pilot study aims to investigate the relationship between raised ICP and length of stay (LOS) in adults admitted to a neurological intensive care unit (neuro-ICU). Materials & Methods: ICP was measured in ten patients admitted to the neuro-ICU following TBI and data from the first 24 hours was analysed. The PTI is a bounded area under the curve, where the bound is the threshold limit of interest for the signal. The upper bound of 20 mmHg for ICP is commonly used in clinical practice. To fully investigate the relationship between ICP and LOS, further bounds from 1 to 40 mmHg were used during the PTI calculations. A backwards step Poisson regression model with a log link function was used to find the important thresholds for prediction of full LOS, measured in hours, in the neuro-ICU. Results: The fit was assessed using a chi-squared deviance goodness of fit method which showed a non-significant p-value of 0.97 indicating a correctly specified model. The backwards step strategy, minimising the model’s Akaike Information Criteria (AIC) at each change, found that levels 13-16, 18 and 20-21 combined were the most predictive. From this model it can be shown that that for every 1 mmHg*hour increase in burden, as measured by PTI, the LOS has a base exponential increase of approximately 2 hours with the largest increases to the LOS given at the 20mmHg threshold level. Conclusions: This model demonstrates that increased duration of raised ICP in the early monitoring period is associated with a prolonged length of stay in neuro-ICU. Further validation of the PTI model in a larger cohort is currently underway as part of the CHART-ADAPT project. Secondly, further adjustment with known predictors of outcome, such as severity of injury, would help improve the fit and validate the current combination of predictors.

Item Type:Book Sections
Glasgow Author(s) Enlighten ID:Kinsella, Professor John and Piper, Dr Ian and Hawthorne, Dr Christopher and Moss, Dr Laura and Shaw, Dr Martin
Authors: Shaw, M., Moss, L., Hawthorne, C., Kinsella, J., and Piper, I.
Subjects:Q Science > QA Mathematics
R Medicine > R Medicine (General)
College/School:College of Medical Veterinary and Life Sciences > School of Medicine, Dentistry & Nursing
Journal Name:Acta Neurochirurgica: Supplementum
Journal Abbr.:Acta Neurochir. Suppl.
Published Online:01 March 2018

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
677341Connecting healthcare and research through data analysis provisioning technology (CHART-ADAPT)John KinsellaInnovate UK (INNOVATE)102113 344237MVLS MED - ANAESTHESIA